Walking, Aging & Bone Strength

Can walking actually strengthen your bones?

In this episode of Why Walking Matters: The Science Explained, we explore the science behind walking and bone health. Learn how walking helps maintain bone density, why weight-bearing movement matters as we age, and how regular walking may reduce fracture risk and support long-term mobility and independence.

We also discuss osteoporosis, fall prevention, aging, and why simple daily movement can have powerful long-term effects on the body.

Links to sources used in this episode:

American Journal of Medicine (1994)
https://pubmed.ncbi.nlm.nih.gov/8304358

ScienceDirect full article page: https://www.sciencedirect.com/science/article/pii/0002934394901112

Journal of Geriatric Physical Therapy (2005)
https://pubmed.ncbi.nlm.nih.gov/16386172

NCBI review page:
https://www.ncbi.nlm.nih.gov/books/NBK71937/

Age and Ageing Journal
https://pubmed.ncbi.nlm.nih.gov/9271287/

Scientific Reports (2025)
https://www.nature.com/articles/s41598-025-29673-0

https://www.health.harvard.edu/healthy-aging-and-longevity/the-best-exercises-for-your-bones

https://www.health.ny.gov/publications/2047/

https://howardluksmd.substack.com/p/your-bones-are-far-more-complicated?fbclid=IwdGRjcAR2mRFjbGNrBHaBzmV4dG4DYWVtAjExAHNydGMGYXBwX2lkDDM1MDY4NTUzMTcyOAABHv81ob7JXyxuzoZti77Bgt_XnltSc09CXkoIjeQ7ZRgLFKUKpAxCAO-90uAE_aem_MnunUjOfk07dTDaPdqoGpg&utm_id=97758_v0_s00_e232_tv2_tp1_a1demo0jrcmyow

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Transcript

SPEAKER_00 0:03

Welcome back to White Walking Matters The Science Explained, the podcast where we explore how one of the simplest human movements can profoundly affect our bodies, brains, and lives. I'm Tatiana, your host. I hope you enjoyed last week's story about walking on the Appalachian Trail. It was an unusual one, and a bit of a divergence from our usual format, but still fun, I think, and we'll try to do more of those during the summer months. Today we're talking about something we don't usually think about until much later in life, bone health. When we think about strengthening bones, we usually picture calcium supplements, milk commercials, or maybe intense strength training. But walking, walking rarely gets mentioned. And that's a mistake, because our bones are living tissue. They are constantly breaking down and rebuilding themselves. And one of the signals that tells your bones to stay strong is mechanical stress, in other words, movement, especially weight bearing movement. And walking is one of the most accessible forms of weight bearing exercise there is. Today we'll explore how bones actually change over time, why walking helps maintain bone density, what the science says about osteoporosis prevention, why consistency matters more than intensity, and how walking can help people age with greater strength, stability, and independence. Let's get started. In the first place, bones are not static. From HowardLuxMD.substat.com, your bones are far more complicated and consequential than you think they are. The skeleton you're walking around in today is not the one you had ten years ago. Most of it isn't even the one you had three years ago. Your bones are continuously being broken down and rebuilt by an army of specialized cells that never stop. By the time you finish reading this post, your body will have dissolved and replaced a small but measurable amount of bone. The entire adult human skeleton turns over completely every gram of it, approximately every ten years. Some regions, like the spine, replace themselves even faster than that. This is one of the most sophisticated maintenance systems in biology. And when it works correctly, it keeps your skeleton strong, damage free, and structurally optimized for the loads you place on it throughout your life until it doesn't. When it stops working correctly, which happens to nearly all of us to some degree after midlife, women after menopause, and many who don't load their skeleton, the consequences are fractures, deformity, loss of independence, and a mortality risk that most people dramatically underestimate. I love bones. This article reveals how fascinating and complicated bone biology and physiology are. It's a bit long, but it goes deep. I've been an orthopedic surgeon for thirty years. I have fixed hundreds of fractures. I have operated on spines, hips and wrists weakened by osteoporosis, and in my experience, almost nobody understands what a bone actually is, its role in our overall health or why it fails. Most people think of bone the way they think of the steel frame of a building, static and structural, either it's intact or it's broken. This mental model is wrong, and understanding why it is wrong is the foundation for understanding how to actually protect yourself. Your skeleton is not a fixed structure, it is a living tissue that is constantly being renewed. Right now, specialized cells are dissolving small sections of your bone while other cells are rebuilding them. This process never stops. It runs continuously from birth until death, and when it falls out of balance for any of several well understood reasons, bone loss begins. Let's get into this. Why the body destroys and rebuilds its own skeleton? The first question is the most counterintuitive one. Why does the body bother? Why dissolve the bone you already have? There are two primary reasons, and both are essential to survival. First, structural maintenance. Bone is subjected to mechanical stress every day, walking, running, carrying, absorbing impact. Over time, that stress creates microscopic cracks in the bone matrix. These cracks are normal and unavoidable. Left unrepaired, they accumulate and propagate, eventually leading to structural failure, a stress fracture, a compression fracture, or worse. The remodeling system exists to identify these micro damaged sites and replace the compromised bone with fresh, structurally sound material before failure. This is why you can build your run slowly over time and eventually run a hundred mile race. But if you try to do that without preparation, you would develop stress fractures in any number of places. Over time, your bones can respond to stress, harden, and become better able to withstand more stress and strain. This is not all that different from what happens in our muscles and tendons. We work out, we get micro tears, and over the next few days, specialized cells rebuild the tendon and muscle tissue. Second, calcium and phosphorus homeostasis. Bone is the body's primary reservoir for calcium. Approximately ninety nine percent of the body's calcium is stored in the skeleton. Calcium is not just a structural material, it is essential for muscle contraction, nerve transmission, cardiac function, and blood clotting. When blood calcium levels drop, the body has to get it from somewhere. Bone is that somewhere. The remodeling system doubles as a calcium bank withdrawable on demand when the rest of the body needs it. This is why skeletal health and metabolic health are inseparable. Your bones are not passive scaffolding. They are metabolically active organs in ongoing conversation with the rest of your body. We'll discuss the components of metabolic health again later. Important, when do we reach peak bone mass? These are numbers I think are worth understanding. Certainly, before we get to the clinical thresholds and to everything that goes into assuring we hit our 50s and beyond with as much bone mass as possible, as well as a critical understanding of all the underlying variables. This is the most relevant if you have teenagers or young adults in your life. Peak bone mass, the highest density your skeleton will ever achieve, is reached somewhere between your mid-20s and age 30. About 40 to 60% of total adult bone mass is accumulated during puberty alone, and roughly 95% of a young woman's peak is in place by age 20. After that, the trajectory is in one direction. You spend the rest of your life drawing down on whatever accounts you built in those years. This is why physical activity and adequate calcium and vitamin D in adolescence and young adulthood are the single most important determinant of where your baseline starts when the inevitable losses of midlife begin. A higher peak means more buffer before you cross clinical osteopenia thresholds. A lower peak built during sedentary teenage years on a calcium poor diet means you arrive at fifty with less margin than your peers and less time to do something about it. The best bone health intervention for your future self might have happened twenty or thirty years ago. The second best is whatever you do starting now. And since women in particular will spend more time in a hospital for osteoporosis related fractures than breast cancer and heart disease combined, this is an important topic to understand. And more than a third of men over fifty have either osteopenia or osteoporosis, and most of them have no idea because men are rarely screened and bone health is culturally framed as a women's issue. Men are not immune to the ravages of reduced bone mass. How bone remodeling actually works? The cellular machinery of bone remodeling involves two principal cell types that work in a tightly coordinated sequence. Oseoclasts are the demolition crew. These are large multi nucleated cells derived from the same lineage as immune cells. They attach to the bone surface, create a sealed acidic environment beneath them, and dissolve the bone's mineral and protein matrix through a combination of acid secretion and enzyme activity. The result is a small pit or trench, a resorption cavity carved directly into the bone. Osteoblasts are the construction crew. These cells are derived from mesenchymal stem cells, the same precursors that give rise to cartilage, fat, and muscle. After osteoclasts have finished resorbing a section of bone, osteoblasts move in, lay down new collagen matrix, and then orchestrate the mineralization of that matrix with calcium and phosphate crystals. The result is new structurally organized bone that replaces the removed material. That was really powerful listeners, and we'll recap and summarize at the end of the podcast. But secondly, why walking helps bones? From Harvard Health Publishing, the best exercises for your bones. Just like every part of your body, your bones need maintenance to be healthy and strong. Exercise is one of the pillars of bone care and fall prevention. By taking steps now, you can help maintain the bone mass you have and maybe even build a little more, reducing your risk of debilitating fractures later in life. Certain types of exercise can increase muscle mass, which in turn enhances strength, muscle control, balance and coordination. Good balance and coordination can mean the difference between falling and suffering a fracture and staying on your feet. In fact, strong evidence shows that regular physical activity can reduce falls by nearly a third in older adults at high risk of falling. All exercises for bone strength have one or more of the following attributes. Provide resistance. In these forms of exercise, you challenge your muscles by working against some type of resistance, such as dumbbells, elastic bands, or even your own body weight. Resistance exercises, including classic strength training, rely on muscle contractions that tug on bones to stimulate them to bulk up. Weight bearing Weight bearing exercise is any activity such as running, walking, dancing, hiking, climbing stairs, or playing tennis, golf or basketball in which you carry your body weight and work against gravity. This contrasts with non weight bearing activities such as swimming or cycling, where the water or bicycle supports your body weight. The force you exert to counteract gravity when you do weight bearing activities is what stimulates bones to get stronger. Provide impact. When you land a jump or pound the ground with each step as you run, you multiply the weight bearing effect of gravity. That's why higher impact activities generally have a more pronounced effect on bone than lower impact activities. Higher velocity. Impact can be increased even more as your speed increases. For example, jogging or fast paced aerobics will do more to strengthen your bones than a leisurely stroll or slow calisthenics exercises. Involve sudden changes of direction. Change in direction while you're moving also appears to benefit bones. When researchers reviewed bone strength in the hips of a variety of athletes, they found that those who played sports such as soccer and squash, which involved rapid turns and start and stop actions had bone strength similar to those who did high impact sports like triple jumpers and high jumpers, and they all had greater bone density than long distance runners. Improve balance. Exercises that target balance may not be the best for building bone, but they will help keep you from falling, so they also serve a bone protecting function. So listeners, why does walking help exactly? The answer comes down to force. Bones respond to load. Every time your foot strikes the ground while walking, a small amount of force travels through your skeleton. Your body interprets that stress as a signal. Essentially, these bones are being used. We should maintain them. This process stimulates bone remodeling and helps slow the decline in bone density. Walking isn't the highest impact activity possible. Running and jumping place greater stress on bones. Strength training is also extremely effective for bone health, but walking has several major advantages. It's low risk, it's sustainable, it's accessible to many people, and people are far more likely to continue doing it long term. And consistency matters enormously for bone health because bones respond to repeated signals over time, not occasional bursts of extreme effort, but a daily walk repeated for years can become a powerful protective habit, especially for aging adults. So what does the science say about walking and osteoporosis? Osteoporosis is a bone disease that causes bones to become weak, brittle, and highly porous. It occurs when your body loses too much bone mass, makes too little bone or both. Osteoporosis is often called a silent disease because bones do not hurt as they thin. You typically do not feel or see it happening. The first noticeable sign is usually a sudden fracture, a broken bone, from a minor fall or even normal daily activities. Other late stage signs include a loss of height, stooped posture, or sudden back pain from a spinal fracture. From the New York State Department of Health, what can I do to prevent osteorosis and broken bones? 1. Eat a variety of healthy, nutrient-rich foods every day. Eat several servings of fruits and vegetables each day. The average person should eat four and a half cups of fruits and vegetables every day. 2. Get the calcium you need. Consume 1,000 to 1200 milligrams of calcium each day. It is best to get calcium from the foods you eat. Foods rich in calcium, such as low-fat dairy foods, milk, yogurt, cheese, dark green leafy vegetables like bok choys, broccoli, collardreens, kale, and turnip greens, canned fish like sardines and salmon, eaten with bones, or calcium fortified with calcium added foods. Try to eat a calcium rich food at each meal. Add calcium supplements only when you cannot get the calcium you need from food alone. 3. Get the recommended amount of vitamin D. There are only a few good natural sources of vitamin D, including fatty fish such as catfish, eel, mackerel, salmon, sardines, and tuna. Small amounts of vitamin D are added to all milk and some types of soy milk, rice milk, almond milk, yogurt, cheese, juice, and nutrition bars. Check with your healthcare provider to find out how much vitamin D is recommended for you. It is likely that you will need a vitamin D supplement to get enough vitamin D. Be physically active. Your bones get stronger and denser when you make them work. Walking, climbing stairs, and dancing are impact or weight-bearing exercises that strengthen your bones by moving your body against gravity when you're upright. Resistance exercises, such as lifting weights or using exercise bands, strengthen your bones and your muscles too. Tai Chi is an example of physical activity that improves posture and balance to help decrease your risk of falls and fractures. Exercise can be easy. Try 10 minutes at a time, adding up to the minutes to reach your goal. 4. Don't smoke. 5. Limit alcohol. 6. Take action to prevent falls. Most broken bones occur as a result of a fall that could have been prevented. Some actions to prevent falls at home include using night lights, removing or securing scatter rugs, and getting rid of clutter. 7. Get a bone mineral density test when indicated. So listeners, research consistently shows that physically active people tend to have better bone density than sedentary individuals. Walking appears especially helpful for maintaining bone health in the hips and the lower spine, areas where fractures can become devastating later in life. Studies on postmenopausal women have found that regular walking. Is associated with slower bone loss and reduced fracture risk. Even moderate walking routines can make a difference. One reason this matters is because fractures in older adults can create a cascade of problems. A hip fracture isn't just a broken bone. It can lead to reduced mobility, hospitalization, loss of independence, social isolation, and declining overall health. So when we talk about walking for bone health, we're not only talking about density scores on a scan, we're talking about preserving the ability to move through life, to remain independent and recover more effectively from setbacks, to stay physically capable. And walking helps in another important way. It improves balance and muscle strength. That matters because preventing falls is just as important as strengthening bones. Even strong bones can fracture under the wrong conditions. Walking improves coordination, leg strength, reaction time, and stability. So walking helps reduce both sides of the equation, lower bone loss and lower fall risk. And that combination matters. Now you might be wondering, is any walking enough? Or are certain types better for bone health? Generally speaking, brisk walking tends to provide more benefit than very slow walking because it creates greater loading forces. Walking uphill can also increase the stimulus. Stairs are excellent. Hiking on uneven terrain may provide additional benefits because your body has to stabilize and adapt constantly. But it's important not to overcomplicate this. The best walking routine is the one you'll consistently maintain, especially if you're currently inactive. Going from sedentary to regular walking is a major positive shift. Even 20 to 30 minutes a day done consistently can help support long-term health. And if you're able to safely add hills or go at a faster pace, stairs, or do longer walks, those may provide additional benefits. It's also worth saying this. Walking works best as part of a broader approach to bone health. That includes adequate protein, calcium, vitamin D, strength training when possible, sleep, and avoiding smoking. Bones are influenced by many systems. Walking is powerful, but it works within the larger picture of overall health. So a quick recap, listeners, that one of the biggest misconceptions about the body is that bones are fixed. And we tend to think of them as permanent structures like scaffolding, but bones are alive. Your skeleton is constantly remodeling itself. Specialized cells break down old bone and build new bone. Throughout life, your body tries to maintain a balance between these processes. When we're younger, bone formation tends to outpace bone loss, but as we age, especially after midlife, that balance changes. Bone density gradually declines. For women, this accelerates after menopause because estrogen plays a major role in protecting bone mass. For men, bone loss usually happens more gradually, but it still occurs. And over time, lower bone density can lead to osteoporosis. Osteoporosis literally means porous bone. Bones become weaker, more fragile, and more susceptible to fractures. Hip fractures, spinal fractures, and wrist fractures become much more likely. And what's important is that bone loss often happens silently. Most people don't know their bones are weakening until they suffer a fracture. That's why prevention matters. And movement is one of the most powerful tools we have. Walking for bone health is really an investment in your future mobility. Research shows older adults can still improve physical function, strength, and stability through regular movement. The body remains adaptable even later in life. So today's takeaway is simple. Walking may seem ordinary, but your bones experience it as information. Every step tells your body this structure is still needed, and over time those repeated signals matter. Walking won't make someone invincible. It's not a magic shield against aging, but it is one of the most accessible ways to support stronger movement, healthier aging, and better long-term resilience. And often the most powerful health habits are the ones simple enough to repeat. This episode was jam-packed of information, listeners. Remember, links to all sources used in the podcast, even if they weren't read aloud, can be found in the podcast show notes or description. If you enjoyed this episode, be kind, share with a friend. And as always, head over to whywalkingmatters.com and share your walking story or ideas for the podcast. Thank you for listening to Why Walking Matters The Science Explained. Until next time, keep walking.